WO2001033659A1

WO2001033659A1 - Mechanically rechargeable metal air battery

Info

Publication number: WO2001033659A1
Application number: PCT/CA2000/001260
Authority: WO
Inventors: Alexander M. Iarochenko; Evgeny B. Kulakov; Oleg I. Krakhin; Stanislavs D. Seruk
Original assignee: Aluminum-Power Inc.
Priority date: 1999-10-29
Filing date: 2000-10-26
Publication date: 2001-05-10
Also published as: AU1014301A

Abstract

An improved metal-air fuel cell comprising at least one non-consumable gas-diffusion cathode; at least one consumable anode; an aqueous electrolyte containing metal ions; at least one ion-exchange membrane; a housing enclosing said electrolyte, said at least one cathode and said at least one anode; a first unit comprising said housing and said at least one cathode; a second unit comprising said at least one anode and said electrolyte; the improvement wherein said electrolyte is contained within an electrolyte impermeable container, said second unit is adapted to be replaceably, received in sealing engagement within said first unit; and puncture means to effect puncture of said electrolyte impermeable container and allow said electrolyte to make contact between said at least one anode and said at least one cathode when said second unit is received within said first unit. The invention is distinctive in that the current source consists of two units having different functions: a non-replaceable unit representing a body with cathode(s), channels and chambers for intake and distribution of electrolyte and air, and collection of the reaction products and a replaceable unit containing consumable anode(s) and electrolyte. In the non-activated state the non-replaceable unit and the cartridge are separated, and to activate the current source it is required to insert mechanically the cartridge into the non-replaceable unit. The mechanical removal of the cartridge from the non-replaceable unit results also in removal of the consumable materials and the by-products of the chemical reaction.

Description

MECHANICALLY RECHARGEABLE METAL AIR BATTERY

FIELD OF THE INVENTION

This invention relates to metal-air electrochemical batteries and fuel cells particularly aluminum-air batteries suitable for electronic devices, including radiotelephones, portable audio and video players, video cameras, and personal computers.

BACKGROUND OF THE INVENTION

There are known electrical rechargeable batteries comprising a housing with a pack of solid state cells, with a converter (controller) for stabilization of the output operating voltage when during the discharge cycle the voltage deeps almost to one-half. In U.S. Pat. No. 5,656,876, a battery pack of lithium or Nl-Cd solid-state cells is shown, where a DC/DC converter provides a stable operating voltage, possibly also different voltages upon request. U.S. Pat. No. 5,286,578 shows a flexible electrochemical cell having an air cathode, a metallic anode and an electrolyte chamber. The electrolyte chamber is collapsed when the battery is shipped (without electrolyte) to save space. U.S. Pat. No. 5,554,918 shows a mechanically rechargeable battery of a cylindrical shape having a replaceable zinc anode, an air electrode (one option) and housing. A non- spillable electrolyte is contained in the housing. When necessary, the anode can be removed an d replaced with a new anode. The energy density of these cells is up to 100 to 180 Wh/L. Further related battery art is found in U.S. Patents. Nos. 3,798,527 3,876,471 ; 3,801,376 ; 3,876,471; 3,915,745; 4,091,174; 4,477,539; 4,871,627 4,925,744; 4,950,560; 4,950,561; 5,004,654; 5,049,457; 5,024,904; 5,032,474 5,415,949; 5,424,147; 5,525,895; 5,318,861, 5,569,551 and 6,060,196

However, the aforesaid prior art collectively suffers from the disadvantages of:

- provide only a limited time of uninterrupted power; require periodic recharging from the electric network; - use of non-renewable sources of raw materials;

- the formation of ecologically harmful waste products;

- relatively high cost; having low mass-energy characteristics;

- high environmental impact (difficult to recycle/heavy metals); and

- low energy resource.

There is, therefore, a need for improved batteries and fuel cells which reduce the aforesaid disadvantages.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide improved batteries which: - provide an independent, self-contained, electrical source that can be mechanically recharged; having a relatively simple structure;

- avoids the need for electrical recharging from the supply network and is, thus, an independent power source; - has increased reliability as an independent source of electrical current;

- offers increasing time to supply uninterruptible power during the conversion and stand-by cycle; provide an electrical power source that remains environmentally and ecologically clean throughout its full life cycle, including manufacture, use, and recycling or disposal; lowers the life cycle cost of manufacturing, usage, and maintenance.

Accordingly, the invention in one aspect provides a battery comprising: at least one non-consumable gas-diffusion cathode; at least one consumable anode; an aqueous electrolyte containing metal ions; a housing enclosing said electrolyte, said at least one cathode and said at least one anode; a first unit comprising said housing and said at least one cathode; a second unit comprising said at least one anode and said electrolyte; the improvement wherein said electrolyte is contained within an electrolyte impermeable container, said second unit is adapted to be replaceably, received in sealing engagement within said first unit, and puncture means to effect puncture of said electrolyte impermeable container and allow said electrolyte to make contact between said at least one anode and said at least one cathode when said second unit is received within said first unit.

Thus, the battery generally comprises, in combination, a body having a non- consumable gas-diffusion cathode and a replaceable cartridge containing the consumable anode and consumable electrolyte. The cartridge provides, in effect, mechanical recharging means.

The second unit is replaceably and sealingly arranged in the first unit, so that when the at least one anode and the electrolyte are consumed, the used-up second unit is removed and a new second unit is inserted. The electrolyte-impermeable container is penetrated by a puncture means after the second unit has been fully inserted into the first unit, to allow the electrolyte to flow between the cathode and anode.

The battery has been constructed to allow intake of air, further distribution of electrolyte, and furthermore to collect the products of reaction. The puncture means or element, preferably, comprises a U-shaped element having sharp ends inside the electrolyte-impermeable container. The battery further includes means for pressing the electrolyte- impermeable container against the sharp ends, to cause the electrolyte- impermeable container to break.

In one embodiment, the penetrating means includes a thread, which is attached to the electrolyte- impermeable container. In another embodiment, the penetrating means includes a push-bar having a pedestal-like end, which is touching against the electrolyte- impermeable container.

The cathodes and anodes form pairs of one cathode and one anode. Pairs in one embodiment are connected in series to produce a desired output voltage. Alternatively, the pairs are connected in parallel to produce a desired output current.

The first unit, most preferably, further comprises at least one first sealing means, forming a hermetic seal between the first unit and the second unit when the first unit and the second unit are engaged.

Alternatively, the second unit further includes at least one second sealing means, forming a hermetic seal between the first unit and the second unit when the first unit and the second unit are engaged. Alternatively, the first unit further includes at least one first sealing means and the second unit further includes at least one second sealing means, the first sealing means and the second sealing means cooperating to form a hermetic seal between the first unit and the second unit when the first unit and the second unit are engaged. The battery, preferably, further includes a cap portion having a third sealing means and a releasable locking means, the third sealing means providing a hermetic seal between the first unit and the second unit, when the first unit and the second unit are engaged, and the releasable locking means is adapted and configured to maintain the body and the second unit in an engaged configuration until released. Preferably, the anode comprises a metal selected from the group consisting of aluminum, zinc, magnesium, and alloys thereof, and further comprising (i) at least 0.02 W/W % Fe and (ii) a metal selected from the group consisting of Ga, In, Th, Sn, Pb, Mn and mixtures thereof, at a cumulative concentration of 0.01 - 5 W/W %; provided that if Fe is at a concentration of less than 0.15% W/W, Mn may only be present at a concentration greater than 0.07 W/W %.

The anode thickness, preferably, is in the range of 0.05 mm to 10 mm, and wherein with the volume of the electrolyte, both are selected to achieve synchronised length of time for using-up anode and electrode.

Preferably, the electrolyte contains metal cations selected from the group consisting of alkali metal cations and alkaline earth cations; and an additive selected from the group consisting of

(a) metal cations of Pb, Sn, Ga and In at a cumulative concentration of 0.001 to 1 M; provided that when Pb, Ga and In is absent the concentration of Sn is greater than >0.2M; and provided that in the presence of both of Mg and Sn together, the concentration of In is greater than 0.2M;

(b) an organic additive selected from the group consisting of 1-15% W/W of a D- glucose based polysaccharide, 0.5 - 5% W/W of a polyester, 0.5% of an aliphatic alcohol selected from ethyl alcohol and propyl alcohol, and mixtures thereof: and

(c) a halide anion selected from the group consisting of F^", Cl^", Br^", I^" and mixtures thereof . Advantageously, the cathode includes additives selected from the group consisting of lead oxides and silver-indium alloys, to provide stabilization of properties during extended storage of the cathode and increase in electrochemical activity while the battery is in use.

Preferably, the first (non-replaceable) unit comprises at least one membrane, the membrane being permeable to hydrogen and impermeable to liquids. Advantageously, the gap between the two electrodes that is being created when inserting the replaceable unit into the non-replaceable unit, is, most preferably, chosen to be the minimum practicable based on construction considerations, and wherein a desired reserve of the electrolyte is contained in chamber(s) arranged in the first unit and in the second unit. The anode may be also U-shaped and cover the electrolyte impermeable container.

The first unit further advantageously includes a current converter for providing conversion of a direct current of the battery into an alternating current, and stabilization of the voltage output of the battery. Alternatively, the first unit further comprises a voltage converter for providing conversion of a direct voltage of the battery into a different level of voltage and stabilization of the voltage output by the battery.

The consumed materials claimed in this current source are ecologically clean during the generation of current, operation and maintenance, and disposal process. An hydrate metal oxide, for example, of aluminum is a most preferred material for the anode using the Bayre process for re-generation to obtain the anode metal. Used-up electrolyte as well as hydrate metal oxide further can be re-cycled.

The battery advantageously comprises 1,2 — N negative electrodes and N+l or N-l of cathodes connected to each other in series, in parallel, or combinations thereof. The anode, preferably, has a thickness of between 0.04 to 0.5 of the spacing between the electrodes, inside a volume of an active part of the second unit.

The cathode, preferably, includes a multi-layer porous membrane, having a water repellent layer, a gas permeable layer and a catalytically active layer, and an open groove on one side surface of for the assembly of the second unit. BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more clearly understood, preferred embodiments thereof will now be described in detail by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic representation of the operation of a metal-air battery according to the prior art;

Fig. 2A is a schematic side view of a gas-diffusion cathode assembly according to a first embodiment of the invention; Fig. 2B is a schematic side view of an anode/electrolyte assembly according to a first embodiment of the invention;

Fig. 3 is a graph showing the relative anode potential HqO as a function of the amount of additive Da in the anode composition;

Fig. 4 is a graph showing the relative anode potential HqO as a function of the current density J and amount of additive Da in the anode composition;

Fig. 5 is a graph showing the load density Q as a function of the amount of an additive Da in the anode composition;

Fig. 6 is a graph showing the density of the corrosion current of the anode as a function of the amount of an alternative additive Be in the electrolyte composition;

Fig. 7 is a schematic side view of a hermetic seal according to a second embodiment of the invention;

Fig. 8 is a graph showing the battery voltage-ampere characteristics for different types of cathode compositions; Fig. 9 is a graph showing the battery voltage-ampere characteristics for different types of anode compositions; Fig. 10 is a graph showing the battery discharge characteristics for different types of anode compositions; Fig. 11 is a graph showing the battery energy as a function of the discharge current density for different types of anode compositions; Fig. 12 is a graph showing discharge characteristics of a battery according to the invention;

Figs. 13a and 13B are graphs showing the current density and power output, respectively, of a battery according to the invention; Fig. 14A is a schematic side view ofan anode/electrolyte assembly according to a third embodiment of the invention, showing the width of the assembly;

Fig. 14B is a schematic side view ofan anode/electrolyte assembly according to a third embodiment of the invention, showing the thickness of the assembly;

Fig. 15A is a schematic side view of an anode/electrolyte assembly according to a fourth embodiment of the invention, showing the width of the assembly;

Fig. 15B is a schematic side view of an anode/electrolyte assembly according to a fourth embodiment of the invention, showing the thickness of the assembly;

Fig. 15C is a schematic top view of an anode/electrolyte assembly according to a fourth embodiment of the invention; Fig. 16A is a schematic side view ofan anode/electrolyte assembly according to a fifth embodiment of the invention, showing the width of the assembly;

Fig. 16B is a schematic side view ofan anode/electrolyte assembly according to a fifth embodiment of the invention, showing the thickness of the assembly;

Fig. 17 a schematic side view ofan electrolyte bag depressing assembly according to a Fig. 16A;

Fig. 18 a schematic side view of a battery according to Fig. 16A, showing a starting position of the electrolyte bag in a sequence of compressions;

Fig. 18B is a schematic side view of a battery according to Fig. 16A, showing a first intermediate position of the electrolyte bag in a sequence of compression; Fig. 18C is a schematic side view of a battery according to Fig. 16A, showing a second intermediate position of the electrolyte bag in a sequence of compression;

Fig. 18D is a schematic side view of a battery according to Fig. 16A, showing a third intermediate position of the electrolyte bag in a sequence of compression;

Fig. 18E is a schematic side view of a battery according to Fig. 16A, showing an end position of the electrolyte bag in a sequence of compression;

Fig. 19 is a schematic perspective view of a replaceable cartridge according to an embodiment of the invention;

Fig. 20A is a schematic side view of a replaceable cartridge according to Fig. 19, showing the thickness of the cartridge;

Fig. 20B is a schematic side view of a replaceable cartridge according to Fig. 19, showing the width of the cartridge and the electrolyte bags in an initial state;

Fig. 20C is a schematic side view of a replaceable cartridge according to Fig. 19, showing the width of the cartridge and one electrolyte bag in its fully emptied state;

Fig. 21 A is a schematic side view of a replaceable cartridge battery according to the invention, showing the width of the cartridge;

Fig. 21B is a schematic side view of a replaceable cartridge battery according to the invention, showing the thickness of the cartridge; Fig. 22A is a schematic side view of a replaceable cartridge battery according to the invention, showing the width of the cartridge;

Fig. 22B is a schematic side view of a replaceable cartridge battery according to the invention, showing the thickness of the cartridge; and

Fig. 23 is a diagram showing the discharge characteristics of a battery according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The basic electrochemical process of a metal-air current source can be demonstrated using the aluminium-air battery i.e. fuel cell as an example.

Aqueous solutions of alkali and salts are utilized as electrolytes in aluminium-air current sources. The following electrochemical reactions occur in the alkali solutions:

Anode dissipation of aluminium at the anode (negative electrode) according to equations (1) and/or (2): A1 + 4OH- → AlO₂ ^" + 2H₂O + 3e (1) or

A1 + 4OH- → Al (OH)₄ ^" + 3e (2)

The cathode recovery of the oxygen at the positive electrode (gas- diffusion cathode) according to equation (3):

O₂ + 2H₂O + 4eo 4OH^" (3) cathodic recovery of hydrogen from water at the cathode:

H₂ + 2OH- »2H₂O + 2e (4)

Summing up the current generation and the corrosion reaction is described by respective equations (5) and (6) below:

4Al + 3O₂ + 6H₂O + 4NaOH → 4NaAl(OH)₄ (current generation) (5)

2A1 + 6H₂O + 2NaOH → 2NaAl(OH)₄ + 3H₂ (corrosion) (6)

The solubility of the reaction product is limited, therefore, when the solubility limit is reached, decomposition process of the solution begins according to reaction (7): NaAl(OH)₄ → NaOH + Al(OH)₃ (7)

As a result of which the final reaction product is formed e.g crystalline aluminum hydroxide. This simplified scheme can be represented as a summation of equations for the current formation process:

4A1 + 3O₂ + 6H₂O → 4Al(OH)₃ (8) and for the corrosion reaction:

2A1 + 6H₂O → 2Al(OH)₃ + 3H₂ (9)

Fig. 1 presents reactions, which are shown at their place of origin in the aluminium-air battery.

Although the reaction mechanism in neutral salt electrolytes differs from reaction mechanism in an alkali solution, the summarising processes are adequately represented by equations (8) and (9). A battery 100 comprises a housing 1, an anode (negative electrode) 12 and a cathode (positive electrode) 2. A load 60 is connected to the anode and the cathode during use of the battery. Oxygen (or air) has access to the cathode via an oxygen inlet 20 and an oxygen outlet 30. An electrolyte chamber is located within the housing, so that ions of an electrolyte 16 may flow freely between the two electrodes. Often, the electrolyte may be added to the housing via an electrolyte inlet 40 and removed from the housing via an electrolyte outlet 50. The electrolyte inlet and outlet may be one and the same, i.e. only one opening in the housing.

A first embodiment of the invention is shown in Figs. 2A and 2B. The air-metal power source has a body 1 containing a cathode 2 and a replaceable unit (cartridge) 200, containing anode 12 and electrolyte 16. Thus, power supply recharging is accomplished with mechanical recharging (by replacing the cartridge) thereby assuring a self-contained power source. Figs. 2A and 2B thus illustrate a basic embodiment of the proposed mechanically rechargeable air-metal battery, containing one anode and two cathodes. The battery consists of two main parts, a cathode unit (Fig.2A) and the replacement cartridge (Fig. 2B). The battery includes one body 1, two gas-diffusion cathodes 2, and a voltage regulator 3, which may optionally include a stabilizer, a support 4 for a hermetic seal, and a sealing ring or gasket 5.

The gas- diffusion cathode preferably has a current conducting mesh 6 serving as a current collector, a gas impermeable layer 7, and a gas permeable layer 8. The body of the battery contains special grooves 9 for holding the cartridge and guides 10 for maintaining alignment of the components during assembly and mechanically reinforcing the battery body. During the corrosion of the anode, hydrogen gas is exiting to the atmosphere through the porous cathode. The cartridge has a cover 11, an anode 12, a water impermeable membrane 13, valves 14, a brush for cleaning the cathodes 15, and an electrolyte 16. When using a dense electrolyte, the cartridge may include an additional cavity 17 for water. The cover has flexible elements 18 for sealing and attaching the cartridge to the body of the battery.

When charging the battery, the cartridge is inserted through the opening to the support, whereupon the fixture 18 guides the cartridge along the grooves 9 and guides 10 and onto the sealing supports 4, thereby opening valves 14 to release the electrolyte and activate the battery of the cartridge. After this process the battery is ready for use (Fig. 2B). During connection to the power source, battery starts to produce electric current, based on the scheme on Fig. 1 and equations (1) to (9). The fixture 18 also includes sealing elements that form a liquid-tight seal with the body of the battery (Fig. 2A) to contain the electrolyte solution. After the cartridge and battery body have been properly engaged, when the battery is activated electrical current is produced according to the electrochemical reaction sequence previously outlined in equations (1) to (9).

Moreover, the battery body unit and cartridge are isolated from each other during the inactive mode, while for activation of the source it is necessary to mechanically place the cartridge into the battery body. The expended materials (anode and electrolyte) and reaction products formed from the use of the source are extracted during the mechanical removal of the cartridge from the battery body unit.

As the used-up cartridge is removed from the battery body in preparation for recharging the battery by inserting a new cartridge, the valves 14 are released and again seal the cartridge to contain the used-up electrolyte. Also, as the used-up cartridge is removed, and as the replacement cartridge is inserted, the built-in brushes 15 clean deposits that may have formed on the cathodes.

The consumable materials, which are used in the current source according to the present invention, are ecologically clean during the production of electric current, through its use, and through its disposition through either recycling or disposal. Based on the Bayra process (regeneration to produce the anode metal), metal oxide hydrate, for instance aluminum, serves as an initial source to produce the anode material. Furthermore, the used-up electrolyte and the aluminum oxide hydrate can be used for recycling. The optimum sizes are selected so that the thickness of the anode is, preferably, between 0.04 to 0.5 of the spacing between the cathode and anode (T_κ) of the volume of an active part of the cartridge, V, (not considering the cartridge cover 11, Fig.2B) and are expressed with the following mathematical expressions: V = V_e+V_a; V_e = V_ezh + V_ez;

V_e = qeQ Pku V_a = (qa + qakor) QkP !

Where V_e = is the volume of the electrolyte capacity, cm³

V_ezh ⁼ volume of the liquid electrolyte composition, cm V_ez = volume of the dense electrolyte composition, cm q_e = specific consumption of water from the electrolyte, cm /A-hr;

Q_k= energy capacity (electrical capacity) active part of the cartridge, A-hr; Pki = (0.35-1.8) - construction parameter V_a = volume of used-up anode material cm³ ; qax = specific expenditure of abode material for the electrochemical reaction cm³/A hr; qakor ⁼ specific expenditure of anode material during corrosion cm³/A hr; pu = (1.3-2.0) - second construction parameter;

Ratios between the clearance dimensions of the cartridge length (L ) width (Tk) and height (H_k) is within the range of l :(0.17-0.35):(1.7-4).

In order to attain the required volt-ampere characteristics, the battery can contain

1,2 — N (N is any positive integer) of cathodes and N+l or N-l of anodes connected to each other in series, in parallel, or combinations thereof.

The consumable metallic anode, preferably aluminum or aluminum alloy anode, inside the cartridge, is located inside the cathode assembly between gas- diffusion electrodes (cathodes) at a specified distance for placement of electrolyte, during use of the battery.

The cartridge preferably includes two separate sealing means. The first sealing means is the packing material, which assures a hermetic seal of the cartridge during storage. The packing material is automatically opened when the replaceable anode cartridge is placed into engagement with the corresponding cathode assembly. The second sealing means is a seal for providing hermetic closure after the cartridge (Fig.2B and Fig. 7) is placed into engagement with the cathode assembly.

The electrolyte and anode used are ecologically safe when decomposed, allowing the chemical reaction products to be discarded or, preferably, recycled to extract the anode metal.

Fig. 12 shows that the cartridge does not have a negative effect on the electrical characteristics of the battery. The curves without separator and with separator are essentially identical, the separator being part of the cartridge.

In Figs. 14A and 14B, an embodiment of an anode 12' is shown. The anode comprises a metal plate 19, which has an elongated negative terminal 20 at one end. The negative terminal has a holder 21 fastened to the negative terminal by a fastening means

22. The holder fastens a first sealing means 23 to the anode 12', which first sealing means seals the passage between the anode and the battery housing (not shown) when the anode is inserted into the battery housing. The holder 21 further clamps an anode membrane 24 to the anode, so that the metal plate 19 is covered by the anode membrane. The anode membrane is made of a material which is electrically conducting, ion permeable but impermeable to the products of the chemical reactions taking place in the electrolyte on the anode plate surface. A preferred material is polypropylene. Thus, any products from the anode reactions will be kept inside the anode membrane.

Figs. 15A to 15C show a battery body 1 having two cathodes 2, and two tightening straps 36. The cathodes are preferably glued to the body, using a hermetically sealing glue, and are further fixed by the straps. The straps are preferably covered with a hermetically sealing agent. The straps are advantageously held to the body with holding screws (not shown). A jumper 38 electrically connects the two cathodes. The jumper is preferably soldered to the current carrier of the cathodes. A free end of the jumper serves as the positive current output. The anode 2 has a free end serving as the negative current output. A second sealing means 30 is arranged between the anode assembly (the cartridge 200) and the battery body 1, to create a hermetic seal between them when necessary. A fourth sealing means 37 is arranged to further seal around the anode free end. Sealing is accomplished when the cartridge cover 11 is tightened to the battery body using a set screw 31 and a vantage screw 39. Screw 39 has an opening for removing hydrogen from the inner cavity 35, the opening has a liquid impermeable separation membrane 41 preventing any electrolyte from escaping via screw 39. The hydrogen is formed by the electrochemical reaction of aluminium corrosion at the anode.

In Figs. 16A, 16B and 17, a further embodiment of a system for activation of the cartridge, after insertion into the cathode assembly, is shown. This embodiment has a two-part cartridge cover comprising an upper cover 11a and a lower cover lib. The upper cover is fitted to the lower cover by a set screw 31, which engages threads in the lower cover and pushes the upper cover towards the lower cover via pressure from the screw head. Between the two covers is a second sealing means 30, which is expanded when the covers are fitted together, to provide a hermetic seal between the two covers and the battery housing 1. Further, the upper cover 11a has a first push hole 33 and the lower cover lib has a second push hole 34 for slidingly accommodating a push bar 26. The push bar has a foot end 27, which is larger than the diameter of the push bar, to compress a bag 24 filled with electrolyte when the push-bar "pedestal-type" end is moving away from the upper cover and the lower cover. The electrolyte bag 24 is preferably contained in a U-shaped anode 12 held at the lower cover lib. Inside the electrolyte bag is a puncture element 25, preferably a U-shaped flat piece having sharp points at its ends and running substantially the whole length ofan inner cavity 35 of the battery housing. As the foot end 27 of the push bar 26 is pressed onto the electrolyte bag 24, the points of the puncture element 25 will make holes in the bag, thereby allowing electrolyte to flow into the internal space of the battery housing 1 and make contact with both the anode 12 and the cathode (not shown). Preferably, an extension rod 28 is arranged at the end of the push bar 26 which is opposite the foot end 27, to make it possible to press the pedestal-type end of the push bar all the way down in order to empty the electrolyte bag. When the cartridge is in its storage state, the push-bar pedestal end is in a position adjacent the lower cover lib. The end of the push bar 26 which is opposite the pedestal -type end 27 protrudes out from the upper cover 11a in the storage state. A third elastic hermetic sealing means 32 is arranged between the pedestal-type end 27 and the electrolyte bag 24 and held to the lower cover lib by a fixture means 29, such as a metal neck. The third elastic hermetic sealing means prevents electrolyte from leaking out from the battery housing 1 via the first push hole 33 and the second push hole 34.

In Figs. 18A to 18E is shown the sequence of emptying the electrolyte bag 24 inside the inner chamber 35 of the battery housing 1. The battery housing (cathode assembly) is located in a vertical position. Then, the cartridge 200 is fully inserted into the housing, until the lower cover lib is seated against the battery housing (Fig. 18A). The extension rod 28 is attached to the push bar 26, and the push bar is pressed down into the cartridge (Fig. 18B) until the extension bar 28 has almost reached the top of the upper cover 11a. Thus, when the push bar 26 is pressed into the cartridge, the electrolyte bag is compressed and initially punctured, allowing electrolyte to flow out from the bag. The bag then is obtaining accordion-like shape, whilst the third elastic hermetic sealing means 32 is expanded into the inner cavity 35. The set screw 31 is tighten until it cannot be turned further, making the second sealing means 30 seal the gap between the battery housing and the cartridge (Fig. 18C). After this, the battery can be held in any position, without any risk of electrolyte leaking out. The push bar 26 is pressed further down until the foot end 27 stops against the crumpled up, empty electrolyte bag 24 (Fig. 18D). During this stage, the third elastic hermetic sealing means 32, together with the push rod 26, creates an over-pressure in the inner chamber 35, by displacing all existing air from inside the inner cavity. This eliminates any decrease in the level of electrolyte inside the inner cavity. The used-up battery is shown in Fig. 18E, where the electrolyte volume has decreased as the anode material is being used- up. The cartridge should now be replaced by unscrewing the set screw 31 until the second sealing means 30 no longer seals the gap between the battery housing and the cartridge.

Figs. 19 to 20C show a replaceable cartridge 200 according to a further embodiment of the invention. The anode 2 has a negative terminal 20 at one end. On each side of the anode is a bag 24 of electrolyte arranged. There are two bags, one on each side of the anode. A cartridge cover 11 is holding the negative terminal of the anode, and a second sealing means 30 provides a hermetic seal between the cartridge and the battery body (not shown), when the cartridge is inserted into the battery body. An activation thread 42 is arranged through thread holes 43 in the cover 11. Fifth sealing means 45 are arranged in the thread holes 43, to prevent any electrolyte from leaking out via the thread holes. The activation thread preferably forms a loop outside the cover, and runs through the thread holes into the electrolyte bag compartment of the cartridge, formed by a first protective liquid permeable membrane 44 over both electrolyte bags and the anode. The ends of the activation thread 42 are attached to bottom ends of the electrolyte bags, i.e. the end that is further away from the cartridge cover 11. Thus, when a battery operator pulls on the loop of the activation thread 42, the bottom of each electrolyte bag 24 is pulled towards the cartridge cover and against electrolyte bag puncture elements 25 arranged inside the electrolyte bags. The bags are punctured and electrolyte will flow from the bags out into the inner cavity (not shown) of a battery housing and through both the first liquid membrane 44 and a second liquid permeable membrane 46 arranged around the anode 2. This operation should only be performed when the cartridge is sealingly seated in a battery housing (cathode assembly). The second liquid permeable membrane 46 will not let any reaction products from the anode reaction through, thereby effectively containing these by-products until the cartridge is replaced with a fresh one. Figs. 21 A and 21B show yet a further embodiment of a battery according to the invention. A battery body 1 has two cathodes 2, and a cartridge 200. The cartridge has a cover 11 with a sealing means arranged around a negative terminal end 20 of an anode 12. The cathodes are preferably screwed to the body, using a hermetically sealing agent to seal any leaks in the screw holes. A jumper 38 electrically connects the two cathodes. The jumper is preferably soldered to the current carrier of the cathodes. A free end of the jumper serves as the positive current output. The anode 12 has a free end serving as the negative current output (negative terminal) 20. A second sealing means 30 is arranged between the anode assembly (the cartridge 200) and the battery body 1, to create a hermetic seal between them when necessary. A fourth sealing means 37 is arranged to further seal around the anode free end. Sealing is accomplished when the cartridge cover

11 , together with the anode 12, is fully pressed into the inner cavity 35 of the battery body 1, via the second sealing means 30.

Figs. 22A and 22B show still a further embodiment of a battery according to the invention. A battery body 1 has two cathodes 2, and a cartridge 200. The cartridge has a cover 11 with a sealing means arranged around a negative terminal end 20 ofan anode

12. The cathodes are preferably screwed to the body, using a hermetically sealing agent to seal any leaks in the screw holes. A jumper 38 electrically connects the two cathodes.

The jumper is preferably soldered to the current carrier of the cathodes. A free end of the jumper serves as the positive current output. The anode 12 has a free end serving as the negative current output (negative terminal) 20. A second sealing means 30 is arranged between the anode assembly (the cartridge 200) and the battery body 1, to create a hermetic seal between them when necessary. A fourth sealing means 37 is arranged to further seal around the anode free end. Sealing is accomplished when the cartridge cover 11, together with the anode 12, is fully pressed into the inner cavity 35 of the battery body 1, via the second sealing means 30.

The cathode is preferably a gas- diffusion, multi-layered electrode that can be provided, for example, in disc, coil, flat, cylindrical, or other practical form, containing a conducting mesh and gas-permeable and gas impermeable layers, of a structure which assures the required electrical characteristics and necessary resource. The cathode may also incorporate additives, in quantities up to 200 mg/cm² of cathode area, such as lead oxides (PbO-PbO₂, up to 99% PbO2) and/or alloys of silver and indium (containing up to 99% of silver) to improve the cathode performance. The anode is made from a metal, preferably Al, Zn, Mg, or their alloys, with one or more of the additives selected from the cations of _aGa, In, Tl, Sn, Cd, Pb, Mn and Fe in respective amounts ranging from 0 - 5% W/W to improve the electrochemical characteristics of the battery and lower self-discharge. The anode thickness is preferably selected from the range of 0.05 mm to 10 mm, so that the anode and the electrolyte are used up at the same time.

The electrolyte is preferably made of a dense composition of salts and alkali with additives selected from the cations of Sn Pb Ga In; and polysaccharide based on D- glucose); (polyesters, including amides ethyl and propyl , and alkali or alkaline earth metal halides in order to increase the electrical load, the electrical capacitance, electrical conductance, freeze-stability and assurance of the required potential.

EXAMPLES

Two electrolytes were prepared, the first comprising an aqueous solution of NaCl and the second comprising an aqueous solution of NaCl with additive E_e. These electrolytes were poured into aluminum-air batteries consisting an anode with additive A_a and a gas- diffusion cathode. The batteries were then discharged at current density (j) of 400A/m² for eight hours. Comparison of experimental results show that in both cases when additives were used and a gel was absent the effectiveness, of the power sources is conserved, the voltage in the elements is increased by 0.3-0.5 V (Fig. 3, curve 1 denotes no additive, curve 2 denotes 0.1% Da and curve 3 0.6% Da) and the corrosion rate of the anode is the same or less (Fig. 6). These results demonstrate that a battery according to the present invention has improved energy, working characteristics, and an improved anode depletion coefficient.

Experimental results obtained from embodiments of the proposed aluminum-air battery are shown in Tables 1 and 2. As it is seen from these tables, the proposed source is providing both high performance and stability in means of electro-energetic characteristics. The use of the proposed complex of additives allows us to obtain new qualities for the battery and achieve the unprecedented performance characteristics. Tables 1 and 2 and Figs. 3 to 6 show the effect from the use of these additives. For instance, the use of the additive Da, in quantity for up to 0.8 % by mass will increase the battery energy capacity up to 1.4 times. The use of the additive Be (Fig. 6), in quantity 0.01 - 0.1 % by mass will decrease by more than 10 times the speed of parasitic reaction of anode corrosion in the above mentioned battery. The individual use of each additive separately will improve just one of the selective parameters. However, the combined use of the proposed additives (anode, electrolyte and gas-diffusion cathode complexes of the additives) will improve the overall characteristics of the battery. Our specific research related to battery for radio-electronic devices showed that the selective use of individual additives allows to achieve high volt-ampere, power, and efficiency characteristics during the initial period of battery use. However, they don't remain constant during the whole period of battery use. The combined use of the complexes additives, allow maintenance of the optimal characteristics constant during the whole period of battery use. Fig. 1 1 illustrates the battery discharge characteristics with anode and electrolyte, using a combined complex of the proposed additives. Without the use of additives, these characteristics cannot be achieved.

The additives are used as a catalyst:

Curve 1 - without additives

Curve 2 - additive Ag (5mg/cm²); Curve 3 - additives Pt-Pd (0.5 mg/cm²);

Curve 4 - additive Pb (10 mg/cm²)

Fig. 8 illustrates experimental volt-ampere characteristics of the battery with the use of gas-diffusion electrodes with hydro-phobic, catalytic, and hydrophilic layers, and current collector of the metallic mesh. The battery has different additives (catalysts) incorporated into the gas diffusion cathode wherein -

Line 1 - Carbon cathode;

Line 2 - Ag additives (5 mg/cm2) incorporated into the carbon cathode;

Line 3 - Pt-Pd additives (0.5 mg/cm2) incorporated into the carbon cathode; Line 4 - Pb additives (10 mg/cm.2) incorporated into the carbon cathode.

Fig. 9 shows the battery volt-ampere characteristics with different additives incorporated into an aluminum anode A95 wherein - Line 1 - additives Ga (0.1 mass%); 2- additives In(0.5mass%); 3-additives TI(0.015mass%)

Line 4 - additives Sn(0.15mass%); 5- .additives Cd(0.01mass%); 6- additives Pb(0.02mass%); Line 7 - additives Mn(0.03mass%); 8-additives Fe(0.01mass%);

Line 9 - whole additives 0.01Ga+0.015TI+0.15Sn+0.01Cd+0.02Pb+0.03Mn+0.01Fe% mass). Fig. 10 shows the battery discharge characteristics with different additives incorporated into an aluminum anode A95 wherein - 1 - Ga(0.01mass%); 2- In(0.5mass%); 3-TI(0.015mass%); 4-Sn(0.15mass%);

5 - Cd(0.01mass%); 6- Pb(0.02mass%); 7-Mn(0.03mass%); 8-Fe(0.01mass%); 9Anode(AluminumA95+0.0 lmass%Ga+0.5mass%In+0.015mass%Ti+0.15mass%Sn +0.01mass%oCd+0.02mass%Pb+0.03mass%Mn+0.01mass%Fe) & cathode [carbon+5mg/cm2Ag] alkali electrolyte [20%KOH+0.06moll\Sn+0.02mollPb+0.01mollGa+0.05moll/lIn+5mass%D- glucose+2mass%ethyl alcohol+ 15mass%NaCl] .

Fig. 11 shows the characteristics of the battery energy with different additives incorporated into aluminum anode A95 wherein -

1 - Ga(0.01mass%); 2- In(0.5mass%); 3-TI(0.015mass%); 4- Sn(0.15mass%); 5 - Cd(0.01mass%); 6- Pb(0.02mass%); 7- Mn(0.03mass%); 8- Fe(0.01mass%);

9 - whole additives (0.01 Ga+0.5In+0.015TI+0.15Sn+0.01 Cd+0.02Pb+0.03Mn+0.01 mass % Fe)

Fig. 12 shows the volt-ampere discharge characteristics of the battery with first and second units combined wherein - 1, 2 ( — ) denotes without separator and 3, 4, 5 ( ) with separator.

In Fig. 13 A, line 1 denotes the volt-ampere characteristics and line 2 the power. Fig. 23 shows the discharge characteristics of a 1 mm thick aluminium/indium anode (95% W/W; 5% W/W) in 4 molar sodium hydroxide, with an aluminium hydroxide electrolyte cartridge system, wherein 1 denotes current in amperes, 2 capacity, 3 is electrolyte, and 4 is aluminium hydroxide concentration at 15°C. Table 1. Electrolvtic Characteristics of An Aluminum-Air Battery with Alkali Electrolyte

Electrolyte Volume V=32ml Cross section S=22.1 cm² Specific capacitance Q_ym = 0.159A-hr/ml - 0.138A-hr/gr Temperature T° = 293 °K Current density I Anode potential F_ia Cathode potential F_ik Battery voltage V Time of experiment t Experiment number N

Table 2.

Electrolyte: 4M aqueous salt solution

Anode: aluminum alloy with a base Sn additive

Discharge Current Density: 452.56 A/m²

Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is to be understood that the invention is not restricted to those particular embodiments. Rather, the invention includes all embodiments which are functional or mechanical equivalents of the specific embodiments and features that have been described and illustrated.

Claims

WHAT IS CLAIMED:

1. An improved metal-air fuel cell comprising at least one non-consumable gas-diffusion cathode; at least one consumable anode; an aqueous electrolyte containing metal ions; at least one ion-exchange membrane; a housing enclosing said electrolyte, said at least one cathode and said at least one anode; a first unit comprising said housing and said at least one cathode; a second unit comprising said at least one anode and said electrolyte; the improvement wherein said electrolyte is contained within an electrolyte impermeable container, said second unit is adapted to be replaceably, received in sealing engagement within said first unit; and puncture means to effect puncture of said electrolyte impermeable container and allow said electrolyte to make contact between said at least one anode and said at least one cathode when said second unit is received within said first unit.

2. A battery comprising at least one non-consumable gas-diffusion cathode; at least one consumable anode; an aqueous electrolyte containing metal ions; a housing enclosing said electrolyte, said at least one cathode and said at least one anode; a first unit comprising said housing and said at least one cathode; a second unit comprising said at least one anode and said electrolyte; the improvement wherein said electrolyte is contained within an electrolyte impermeable container, said second unit is adapted to be replaceably first unit, received in sealing engagement within said first unit, and puncture means to effect puncture of said electrolyte impermeable container and allow said electrolyte to make contact between said at least one anode and said at least one cathode when said second unit is received within said first unit.

3. A battery according to claim 2 wherein said container is formed of a plastics material.

4. A battery as claimed in claim 3 wherein said plastics material is selected from the group consisting of a thermoplastic, a thermoset, an elastomer and combinations thereof.

5. A battery according to any one of claims 1, 3 or 4 wherein said battery further comprises at least one first conduit for connecting to and distributing ambient air, at least one second conduit for distributing said electrolyte, and at least one third conduit for collecting reaction products in cooperation said at least one first conduit and said at least one second conduit.

6. A battery according to any one of claims 2 to 5, wherein said puncture means comprises a substantially U-shaped element having sharp ends, said puncture element being arranged inside said electrolyte impermeable container, and said battery further comprises puncturing means for pressing said electrolyte impermeable container against said sharp ends, to cause said electrolyte impermeable container to break.

7. A battery according to claim 6, wherein said puncturing means comprises a thread, which is attached to said electrolyte impermeable container.

8. A battery according to claim 6, wherein said puncturing means comprises a push bar having a pedestral-type end, which contacts said electrolyte impermeable container.

9. A battery according to any one of claim 2 to 8, wherein said at least cathode and said at least one anode form pairs of one cathode and one anode, and said pairs are connected in series to produce a desired output voltage.

10. A battery according to any one of claims 2 to 9, wherein said at least one cathode and said at least one anode form pairs of one cathode and one anode, and said pairs are connected in parallel to produce a desired output current.

11. A battery according to any one of claims 2 to 10, wherein said first unit further comprises at least one first sealing means, forming a hermetic seal between said first unit and said second unit when said first unit and said second unit are engaged.

12. A battery according to any one of claims 2 to 11, wherein said second unit further comprises at least one second sealing means, forming a hermetic seal between said first unit and said second unit when said first unit and said second unit are engaged.

13. A battery according to any one of claims 2 to 12, wherein said first unit further comprises at least one first sealing means and said second unit further comprises at least one second sealing means, said first sealing means and said second sealing means cooperating to form a hermetic seal between said first unit and said second unit when said first unit and said second unit are engaged.

14. A battery according to any one of claims 2 to 13, wherein said at least one cathode is adapted to be replaceable engaged within said first unit.

15. A battery according to any one of claims 2 to 14, wherein said battery further comprises a cap portion, said cap portion comprising a third sealing means and a releasable locking means, said third sealing means providing a hermetic seal between said first unit and said second unit, when said first unit and said second unit are engaged, and said releasable locking means is adapted to maintain said body and said second unit in releasable engagement.

16. A battery according to any one of claims 2 to 15, wherein said anode comprises a metal selected from the group consisting of aluminum, zinc, magnesium, and alloys thereof, and further comprising (i) at least 0.02 W/W % Fe and (ii) a metal selected from the group consisting of Ga, In, Th, Sn, Pb, Mn and mixtures thereof, at a cumulative concentration of 0.01 - 5 W/W %; provided that if Fe is at a concentration of less than 0.15% W/W, Mn may only be present at a concentration greater than 0.07 W/W %.

17. A battery according to any one of claims 2 to 16, wherein said electrolyte contains metal cations selected from the group consisting of alkali metal cations and alkaline earth cations; and an additive selected from the group consisting of (a) metal cations of Pb, Sn, Ga and In at a cumulative concentration of 0.001 to 1 M; provided that when Pb, Ga and In is absent the concentration of Sn is greater than

>0.2M; and provided that in the presence of both of Mg and Sn together, the concentration of In is greater than 0.2M; (b) an organic additive selected from the group consisting of 1-15% W/W of a D- glucose based polysaccharide, 0.5 - 5% W/W of a polyester, 0.5% ofan aliphatic alcohol selected from ethyl alcohol and propyl alcohol, and mixtures thereof: and

(c) a halide anion selected from the group consisting of F^", Cl^", Br^", I^" and mixtures thereof.

18. A battery according to any one of claims 2 to 17, wherein said at least one cathode comprises an effective amount of an additive selected from the group consisting of lead oxides and silver-indium alloys, to provide enhanced stabilization of properties during extended storage of said cathode and enhanced electrochemical activity when the battery is in use.

19. A battery according to any one of claims 2 to 19, wherein said the battery comprises 1,2 ... N negative electrodes and N+l or N-l of positive electrodes connected to each other in series,